A few hours ago, Apple has now permanently blocked the signatures of iOS 13.3. This means that users who have updated their iPhone or iPad to iOS 13.3.1 can no longer revert to iOS 13.3. The update to this firmware is also out of service.
The decision to suspend the signatures of the various iOS has repercussions in particular for the users of the jailbreak. Indeed, a potential jailbreak of iOS 13.3 would now be useless for those who have already installed iOS 13.3.1.